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st: re: overlapping observations in panel

From   Kit Baum <>
Subject   st: re: overlapping observations in panel
Date   Wed, 14 Oct 2009 14:47:49 -0400

Daniel said

I have a general question about how to handle overlapping observations
in a fixed (or random) effects panel regression.  Specifically, I have
quarterly observations of investment, cash flow, and a number of other
variables.  The model specifies a yearly relationship where investment
in a specific product line over the 12 months is dependent on the cash
flow over the same period and the asset base at the beginning of the
12 month period.

If I simply run the regression with all of the observations, I must be
double counting information.  It seems like I only have 1 real
independent observation for every 4 quarterly observations.

If the model says that investment over the last four quarters depends on current cashflow and the asset base four quarters ago, that relationship should hold every quarter; there's nothing sacred about the last quarter of the calendar year. So something like

webuse grunfeld,clear
// tsmktim from ssc
tsmktim yq, start(1990q1) i(company)
g inv12 = invest + L.invest + L2.invest + L3.invest
g kstock12 = L4.kstock
g cashflow = D.mvalue

xtreg inv12 cashflow kstock12, vce(cluster company) fe

makes full use of all available observations in the panel.


Kit Baum   |   Boston College Economics & DIW Berlin   |
An Introduction to Stata Programming |
   An Introduction to Modern Econometrics Using Stata  |

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